A review of factors which may influence the sea‐age and maturation of Atlantic salmon Salmo salar L.

Gardner, Michael L. G.

doi:10.1111/j.1095-8649.1976.tb04680.x

Cited by 67 publications

(47 citation statements)

References 53 publications

(74 reference statements)

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“…Studies on patterns of age and size at maturity in salmonids have a long history (Ricker, 1972;Gardner, 1976), with many examples of population-specific variation (reviewed in Groot and Margolis, 1991;Quinn, 2005;Garcia de Leaniz et al, 2007). Indeed, such patterns provided some of the earliest evidence for the discreteness of salmon populations (Rich, 1939).…”

Section: Introductionmentioning

confidence: 99%

Correlated contemporary evolution of life history traits in New Zealand Chinook salmon, Oncorhynchus tshawytscha

2011

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Size at age and age at maturity are important life history traits, affecting individual fitness and population demography. In salmon and other organisms, size and growth rate are commonly considered cues for maturation and thus age at maturity may or may not evolve independently of these features. Recent concerns surrounding the potential phenotypic and demographic responses of populations facing anthropogenic disturbances, such as climate change and harvest, place a premium on understanding the evolutionary genetic basis for evolution in size at age and age at maturity. In this study, we present the findings from a set of common-garden rearing experiments that empirically assess the heritable basis of phenotypic divergence in size at age and age at maturity in Chinook salmon (Oncorhynchus tshawytscha) populations introduced to New Zealand. We found consistent evidence of heritable differences among populations in both size at age and age at maturity, often corresponding to patterns observed in the wild. Populations diverged in size and growth profiles, even when accounting for eventual age at maturation. By contrast, most, but not all, cases of divergence in age at maturity were driven by the differences in size or growth rate rather than differences in the threshold relationship linking growth rate and probability of maturation. These findings help us understand how life histories may evolve through trait interactions in populations exposed to natural and anthropogenic disturbances, and how we might best detect such evolution.

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Section: Introductionmentioning

confidence: 99%

Correlated contemporary evolution of life history traits in New Zealand Chinook salmon, Oncorhynchus tshawytscha

2011

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“…Ces constatations sont générales sur l'ensemble des rivières bretonnes (FONTENELLE et ai, en prép.). L'absence d'information sur les remontées estivales prend d'autant plus d'importance que la population de saumons du Scorff a pu subir la même évolution que celle observée sur d'autres populations de rivières étrangères : les castillons devenant prépon-dérants dans les remontées annuelles (Ecosse: SHEARER, 1971 ;Irlande: WENT, TWOMEY, 1971 ;TWOMEY, 1972 ;Canada : PEET, PRATT, 1972, RUGGLES, TUR-NER, 1973MILLS, 1971 ;GARDNER, 1976).…”

Section: -Caractéristiques Des Capturesunclassified

L'exploitation des salmonidés à la ligne sur le Scorff, rivière de Bretagne sud

Baglinière¹,

Nihouarn

Champigneulle³

1979

Bull. Fr. Piscic.

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“…A number of possible causes have been postulated. These include changes in the freshwater environment affecting the growth of the juveniles and the subsequent age at maturity of the adults (Gardner, 1976;Anon., 1994), selective exploitation of certain stock components (Gee & Milner, 1980;Moore et al, 1995;Consuegra et al, 2005) and climatic changes affecting the ocean environment (Friedland & Hass, 1996;Bisbal & McConnaha, 1998;Friedland, 1998;Friedland et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Life history changes in Atlantic salmon from the River Dee, Wales

2008

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The change in life history of Atlantic salmon (Salmo salar L.) on the River Dee over the last 60 years is described. Over the last 60 years, salmon have shown a change in run timing, the majority currently entering the river between August and October compared with prior to June. This has coincided with a change in the sea age composition, which was dominated by multi-sea winter salmon prior to the 1980s after which the proportion of 1sea-winter fish increased until they now dominate the mature population. Growth rates of salmon in fresh water remained relatively stable until the mid-1980s and then increased. By the end of the 1990s juvenile salmon were, by the end of their first and second year, respectively, *60 and *19%, on average, larger than they were between the late 1930s and mid1980s. This has been reflected in a change in the age composition of smolts where the mean smolt age has declined from *2 years prior to the 1980s to *1.6 years in the late 1990s. There was no observed trend in post-smolt (marine) growth for salmon. Size at return for 1SW salmon appeared stable while there is some evidence of an increase in mean length of 2SW salmon at the end of the 1990s. A steady state life history model was developed which suggests an increase in the instantaneous rate of mortality by 2.9% from 1. 495 year -1 in 1937/1938 to 1.538 year -1 in 1967/1969 and by 21.6% to 1.870 year -1 in 1997/ 1999. This is considered to explain the shift in mean age at maturity from 5.2 to 4.8 to 3.9 years for the three periods examined. There is close agreement between the observed mean age at maturity and that predicted by the model suggesting optimal lifetime reproductive success.

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A review of factors which may influence the sea‐age and maturation of Atlantic salmon Salmo salar L.

Cited by 67 publications

References 53 publications

Correlated contemporary evolution of life history traits in New Zealand Chinook salmon, Oncorhynchus tshawytscha

Correlated contemporary evolution of life history traits in New Zealand Chinook salmon, Oncorhynchus tshawytscha

L'exploitation des salmonidés à la ligne sur le Scorff, rivière de Bretagne sud

Life history changes in Atlantic salmon from the River Dee, Wales

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